Need help on positioning of 400w HPS

[Zac(Aus)]

Hey guys ive just taken my cfls out and put my 400w in there but idk how close to have it to my plants?
atm its around a meter away from the plants? i hope thats okay?

and another question was wondering when i should top my plants like cut the top off? there 4 weeks old atm

and another question lol, once i get into flowering iheard
tthat you can give your plants co2 by getting like soda water and spraying it on the plants is this true or no?
if it isnt true is it ok to grow without co2?

Cheers :)

 

[Fred]

You can go as close as about 18 inches...about 48 cm on a 400 if the heat is being controlled. What strain do you have? Some do better than others with topping.

 

[SkyHi]

1. Put the light as close as possible without burning them, with a 400 should probably be about 12-18 inches. Just put your hand above the plants and if it feels hot raise it a bit until its as close as possible without burning the plants.

2. you should be able to top them as soon as you have 3-4 internodes...

3. CO2 is not neccessary to grow plants just optional

 

[Zac(Aus)]

its just a bagseed
so wouldnt have a clue

thanks for the info fellas :)

 

[Fred]

just went and measured under my 400 and yup...i'm at 15 inches with no problems...not even air cooling it. So i guess I start at 18-20 and let them grow in until about 12 or so away.

how about the soda water? Heard it never tried it. KC brains said it's good...???

 

[Fred]

here is some great info on training plants in here.



Just one of many ways though. Have fun with it and good luck.

 

[Green Cali]

cool tube

you can also make a cool tube out of a hurricane tube, some proper fit ducting, exhaust fan then you can have the light within 3 inches.

 

[j wizzle]

if you have an inline fan hooked up to an air-cooled hood, you can put that 400w almost touching the plants without any major problems. i have my 600s around 9-12 inches away most of the time.


put your hand under the light, if you can keep your hand there for 30 seconds without any discomfort or heat, you are fine.


i SCROG, google it, and i got almost a pound from a single plant without CO2. just need to get air circulating.